Magnetic resonance imaging apparatus and method for acquiring under-sampled MR signal

Abstract

An MRI apparatus includes a data acquirer configured to under-sample MR signals, respectively received from channel coils included in a radio frequency (RF) multi-coil, at non-uniform intervals to acquire pieces of data set; and an image processor configured to restore pieces of K-space data respectively corresponding to the channel coils by using a positional relationship based on a spatial distance between a reference data set among the acquired pieces of data set and at least two of data set among the acquired pieces of data set, in a K-space.

What is claimed is: 
     
       1. A magnetic resonance imaging (MRI) apparatus comprising:
 a data acquirer configured to divide a K-space corresponding to each of channel coils, which are included in a radio frequency (RF) multi-coil, into corresponding blocks, and under-sample MR signals, which are respectively received from the channel coils, for the corresponding blocks at non-uniform intervals, to acquire pieces of data set; and 
 an image processor configured to restore pieces of K-space data for the corresponding blocks using a positional relationship determined based on spatial distances between a reference data set selected among the acquired pieces of data set and at least two pieces of the acquired pieces of data set in the K-space, respectively. 
 
     
     
       2. The MRI apparatus of  claim 1 , wherein the data acquirer is further configured to apply a same non-uniform under-sampling pattern to the corresponding blocks, to acquire the pieces of data set. 
     
     
       3. The MRI apparatus of  claim 1 , wherein the data acquirer is further configured to apply different non-uniform under-sampling patterns to at least two blocks among the corresponding blocks, to acquire the pieces of data set. 
     
     
       4. The MRI apparatus of  claim 1 , wherein the image processor is further configured to restore pieces of unacquired data set for one of the corresponding blocks, by using the positional relationship, and restore the pieces of K-space data corresponding to the one of the corresponding block, by using at least one from among the restored pieces of unacquired data set and the acquired pieces of data set. 
     
     
       5. The MRI apparatus of  claim 4 , wherein the image processor is configured to set one of the acquired pieces of data set as the reference data set, and determine the positional relationship based on the spatial distances between the reference data set and the at least two of data set of the acquired pieces of data set, respectively. 
     
     
       6. The MRI apparatus of  claim 5 , wherein the image processor is further configured to restore one of pieces of unacquired data set having the first positional relationship with the at least two pieces of the acquired pieces of data set, to acquire restored pieces of data set, and restore other pieces of unacquired data set having the positional relationship with the restored pieces of data set and at least one of the at least two pieces of the acquired pieces of data set. 
     
     
       7. The MRI apparatus of  claim 5 , wherein the image processor is further configured to calculate a spatial correlation coefficient corresponding to the positional relationship, by using the reference data set and the at least two pieces of the acquired pieces of data set, and to restore pieces of unacquired data set by using the spatial correlation coefficient, to restore the pieces of K-space data. 
     
     
       8. The MRI apparatus of  claim 4 , wherein the image processor is further configured to sequentially restore the pieces of unacquired data set, included in each of the corresponding blocks, in a predetermined order. 
     
     
       9. The MRI apparatus of  claim 1 , wherein the data acquirer is further configured to apply different non-uniform under-sampling patterns to the corresponding blocks, to acquire the pieces of data set. 
     
     
       10. The MRI apparatus of  claim 1 , wherein the corresponding blocks are divided into groups, and
 the data acquirer is further configured to apply, to the groups, different under-sampling interval patterns, respectively. 
 
     
     
       11. The MRI apparatus of  claim 1 , wherein the corresponding blocks comprise a first block and a second block, and
 the data acquirer is further configured to apply, to the first block a non-uniform under-sampling pattern different from a non-uniform under-sampling pattern applied to the second block. 
 
     
     
       12. The MRI apparatus of  claim 1 , wherein the first block comprises more or fewer pieces of the acquired pieces of data set than the second block. 
     
     
       13. The MRI apparatus of  claim 1 , wherein the corresponding blocks comprise a first block, a second block, and a third block,
 the second block comprises fewer pieces of the acquired pieces of data set than the first block, and 
 the third block comprises more pieces of the acquired pieces of data set than the first block. 
 
     
     
       14. The MRI apparatus of  claim 13 , wherein the third block is disposed closer to a center line of the K-space than the first block and the second block. 
     
     
       15. The MRI apparatus of  claim 1 , wherein the image processor is further configured to calculate a spatial transform on the restored pieces of K-space data to generate MR images by channel, and acquire a final MR image by using the MR images by channel. 
     
     
       16. The MRI apparatus of  claim 15 , wherein the image processor is further configured to calculate an inverse Fourier transform on the restored pieces of K-space data, to generate the MR images by channel. 
     
     
       17. The MRI apparatus of  claim 15 , wherein the image processor is further configured to calculate a sum of squares or a complex sum of the MR images by channel, to generate the final MR image. 
     
     
       18. The MRI apparatus of  claim 1 , wherein a number of the corresponding blocks and sizes of the corresponding blocks are set based on at least one from among a hardware type of the RF multi-coil and a region of an object to be imaged. 
     
     
       19. The MRI apparatus of  claim 1 , wherein the data acquirer is further configured to apply a non-uniform under-sampling pattern, to acquire the pieces of data set, and
 the non-uniform under-sampling pattern is set based on at least one from among a hardware type of the RF multi-coil and a region of an object to be imaged. 
 
     
     
       20. A magnetic resonance imaging (MRI) method using a radio frequency (RF) multi-coil comprising channel coils, the MRI method comprising:
 dividing a K-space corresponding to each of the channel coils, which are included in the RF multi-coil, into corresponding blocks; 
 under-sampling MR signals, which are respectively received from the channel coils, for the corresponding blocks at non-uniform intervals, to acquire pieces of data set; and 
 restoring pieces of K-space data for the corresponding blocks by using a positional relationship determined based on spatial distances between a reference data set selected among the acquired pieces of data set and at least two of the acquired pieces of data set in the K-space, respectively.